Heightening of buildings. How common is it in your city?
 

By heightening a building, I mean adding new floors on existing building.
Sometimes without even any change at lower levels (or almost if you don't count the new access).

First question. What is the exact term for this in English?

It was quite common in the past, it faded away after the 1950s but it's becoming more common in Paris.
A cheap and easy way to increase density without demolishing buildings.

A rather basic one., I have spotted this week in an inner suburb of Paris.
https://live.staticflickr.com/65535/...22e4fe84_c.jpg
Rue de Bezons, Courbevoie by Minato ku, sur Flickr

https://live.staticflickr.com/65535/...d55e6269_c.jpg
Avenue Marceau, Courbevoie by Minato ku, sur Flickr

In this case, I don't think that the lower levels went unchanged.
https://live.staticflickr.com/65535/...6d3cdd41_c.jpg
Rue Boussingault, 13e by Minato ku, sur Flickr

Here they added two floors on an existing social housing buildings and built new lifts to serves them.
Work was carried out keeping the apartments inhabited.
https://live.staticflickr.com/65535/...29d28248_c.jpg
Rue Vergniaud, 13e by Minato ku, sur Flickr

6 floors being built above a two floors supermarkets. The supermarket remains on activity during construction.
https://live.staticflickr.com/65535/...1e194c16_c.jpg
Place de la Nation, 12e by Minato ku, sur Flickr

I was wondering if it is common in your city ?

Usually the structural system has limited capacity to support additional floors.

However, Chicago has a number of conversions of old industrial buildings that were able to get a vertical expansion... these buildings were designed for heavy loads so they have extra unused capacity after being converted to residential or office use.

It's also common for Chicago bungalows to get a "pop top"... a horizontal expansion would eliminate the backyard, so the only way to go is up (via a pop top) or down (by digging out the basement).

I've seen it happen in NYC, but I don't think it is common. A few years ago Ann Arbor's Pizza House restaurant sold development rights above their building, which was controversial at the time. That apparently kicked off a redevelopment of the entire block into high-rises:

Before: https://goo.gl/maps/MzsEWrp4oYptU2Mb9
After: https://goo.gl/maps/UujxcJA5fJx7zhx98

It's extremely common in NYC. In fact it occurs practically everywhere. The only limits, really, are NIMBYism and strict height laws.

If you go to a rooftop of a historic neighborhood like Tribeca, Flatiron or Soho, you'll basically see nothing but penthouse additions, almost all constructed over the last 30 years. But they're required to be invisible from the street in historic districts, so they're set-back from pedestrian view.

And countless buildings, really everywhere, are rebuilt with additional floors, but it's hard to tell because they usually rebuild the entire building facade. This has been happening since the 1950's. In fact many postwar modernist buildings are prewar buildings that were rebuilt bigger and in a (back then) more fashionable form. I'd say around half of the postwar wedding cake buildings you see in Midtown are actually rebuilt prewars.

And sometimes the same building is rebuilt three or four times. 340 Madison Ave., in Midtown, was a 1920's midrise office building, then was rebuilt in the 1950's to a larger postwar building, then was "modernized" in the 1980's, then was stripped down to steel and rebuilt again, expanding to an adjacent parcel, just a few years ago.

Yeah, penthouses, I knew that. I didn't consider that in the spirit of the thread though. I don't know of a ton of buildings that have added multiple floors like the example in the OP.

That's interesting. Definitely didn't realize that.

In the case of old office buildings in Paris, they usually rebuilt the whole building while keeping the facade.
The floors added are usually a part with a very contemporary architecture.

Two new floors
Before : Rue de la Boetie, 8e
After :Rue de la Boetie, 8e

A new glazed roof
Before :Boulevard Haussmann, 8e
After: Boulevard Haussmann, 8e

Two new floors. It seems that the two buildings on the left have also been heightened but in the past.
Before : Boulevard Haussmann, 8e
After: Boulevard Haussmann, 8e

Here a post office buildings, as the post doesn't need all the space anymore.
They transformed most of the building into offices and added floors.
Before : Rue de Prony, 17e
After : Rue de Prony, 17e

Before : Boulevard Diderot, 12e
After : Boulevard Diderot, 12e

I guess this would count.

We do this a lot in Austin. Build a building on top of an older one.

https://austin.towers.net/atop-a-his...es-a-new-look/

We have a bit of that in London, but its often just a floor/ roof conversion and relatively rare. What's more common is 'deathmasking' where only the exterior is kept.

https://www.fromthemurkydepths.co.uk...Deptford-3.jpg

building at right:

https://i1.wp.com/spitalfieldslife.c...size=600%2C906

That's a fantastic term. The terms I hear in Philadelphia are facadectomy (the equivalent of deathmasking - keeping the historical facade, but building an entirely new building behind it) and overbuilds (adding additional floors to an existing structure). Facadectomies are often done on historically protected structures. Overbuilds are much more common and not confined to protected buildings.

Here is an example of an ambitious overbuild that was just proposed on a historic auction house building (5 stories to 19 stories):

http://www.ocfrealty.com/wp-content/...IMG_9802-1.jpg

http://www.ocfrealty.com/wp-content/...9.42.58-AM.png

Here is an example of a facadectomy (the marble front is from the 1830s):

https://hiddencityphila.org/wp-conte...enn-Mutual.jpg

Whoa.

It's somewhat common in Toronto to build additions above existing buildings. Typically a 3rd/4th/5th storey addition to an older 2 or 3-storey commercial building. Some recent examples off the top of my head:

https://goo.gl/maps/nVbHPrCaQ5uxNgXT7
https://goo.gl/maps/WWHQTmcRCZ9DFdmn8
https://goo.gl/maps/fvNB64FSTT61R49p9
https://goo.gl/maps/AQ75CR6mj32rd4sV8

Slightly larger scale ones:

https://goo.gl/maps/NYsJNqMUEV3PMQy3A
https://goo.gl/maps/okn621KqgbPxQDiQ9

But some of the more extreme cases would involve plopping an entire new skyscraper on top of an existing high-rise. The lower 18 floors of this one were a tower from 1968 that was reinforced via exterior bracing to support a new 37 floor addition above (and then reclad to match):

https://cdn.skyrisecities.com/sites/...9040-30995.jpg


Facadectomies / deathmasking (way cooler term) are also unfortunately very common, but I don't think those really count as none of the existing structural components are being retained. It's not really an "addition" therefore, but a replacement.

The BCBS building in Chicago famously was designed to plop more stories on top. https://en.wikipedia.org/wiki/Blue_C...e_Shield_Tower

In Rochester, MN, where I grew up, they doubled the height of the original Mayo Clinic to, I believe 20 stories. They must have known all along they were going to add floors to it.

This. A constraint that goes to even modern structures like that one over here. They would manage to add only 6 floors to it - probably at a reasonable cost 'cause this is La Défense, not Central Paris - as it is being entirely refurbished. Yet the flexible concrete structure was built in 1970, that's not so old.

So it must be a whole different story to pre-war buildings, like those of the 19th century. Especially when their footprints would be narrow.

What Minato is showing is just regular upgrades within the old central city, and only a matter of a couple of floors in every case. They've been doing this for long to take pretty much everything to the 6/7-storey "Haussmannian" standard.
And back to the days of Haussmann (1850s/60s), new buildings were even slightly shorter, like 4 or 5 stories on average, I think.
It was all made of limestone and old steel; there was no flexible composite material such as concrete yet back then.

Constraints are really heavy in a real old urban fabric. Unless you'd destroy it all, but we'll never do that. We'd rather build taller buildings where they don't cause any harm to anything valuable.

Not very common here in Houston. Those that are were designed and built with the intent to add more floors at a later date. A building in Texas Medical Center added about 20 on a 5 story structure and there's a 10-story building downtown that about 15 stories for a W Hotel.

I have seen picture of projects in Paris that I didn't imagine.
Not always with a good taste

Like this one at the intersection of Rue Lecourbe and Rue Cambronne
http://www.cotec-ing.com/wp-content/...3435302290.jpg

This is what stands at this place. A two and three floors buildings.
They will add five and four floors.
Rue Lecourbe, 15e

^ Je pense que le 2è étage (3rd floor) à l'angle donne du sens à l'immeuble. On dirait que les étages supérieurs sont comme en suspension.

C'est ça qui est bien dans l'achi contemporaine locale. Ils vont chercher des trucs amusants, gadgets originaux, parfois improbables en s'efforçant de coller aux restrictions de chez nous, certes extrêmement sévères.
Sans doute d'ores-et-déjà (et peut-être depuis longtemps) les régulations d'urbanisme les plus contraignantes dans le monde développé.

Sans quoi, ce n'est rien d'exceptionnel en effet. Surtout au prix qu'ils le vendront. Mais le cahier des charges sera probablement satisfait car ce n'est pas un mauvais quartier.

BlueCross BlueShield Illinois

https://photos.smugmug.com/Chicago/C...34_3441-XL.jpg
https://photos.smugmug.com/Chicago/W...MG_4090-XL.jpg